''On the field and off the field, a lot of things happened in these years,'' Zito said. The sides formally parted ways Saturday, when the Giants declined to exercise Zito's $18 million contract option for next season and instead owe the left-hander a $7 million buyout. Barry Zito has known for months he would be leaving the Giants after seven up-and-down years in San Francisco. The 2002 AL Cy Young Award winner across the water for the Oakland Athletics, Zito just completed a $126 million, seven-year contract with the Giants. Louis last year with his team facing elimination as the Giants rallied to win the series in seven games, then won Game 1 in a surprising World Series sweep of the Tigers - after he was left off the postseason roster for all three rounds in 2010. The biggest decision still facing general manager Brian Sabean and assistant GM Bobby Evans is due by Monday: Whether to exercise right-hander Ryan Vogelsong's $6.5 million club option that includes a $300,000 buyout.